Unprecedented Copper(II) Complex with a Topoquinone-like Moiety as a Structural and Functional Mimic for Copper Amine Oxidase: Role of Copper(II) in the Genesis and Amine Oxidase Activity

Copper amine oxidase
(CAO), consisting of the topoquinone (TPQ)
cofactor, catalyzes the oxidation of primary amines to aldehyde. We
have successfully addressed this issue through isolation of a copper
complex which mimics the active-site structure as well as the function
of CAO. This inimitable complex, consisting of two TPQ-like side-arms,
formed by ambient aerial oxidation of a precursor Schiff base complex,
is the most efficient homogeneous catalyst for quantitative oxidation
of primary benzylic amines to corresponding secondary imines under
ambient conditions within 30 min. The longstanding contention of actual
involvement of Cu­(II) in the catalysis is resolved through quenching
experiments of Cu­(II) superoxo species and detailed density functional
theory studies.